Polyethylene terephthalate coloring systems and methods

ABSTRACT

Systems for manufacturing bulked continuous filament having tonal coloring from PET comprise, in various embodiments: (1) an extruder; (2) a static mixing assembly coupled to the extruder comprising: (a) a housing, and (b) one or more individual static mixing elements disposed within the housing; (3) a plurality of colorant ports along a length of the static mixing assembly such that each of the plurality of colorant ports is configured to provide colorant to a polymer stream at a different location along the length of the static mixing assembly; and (4) one or more spinning machines positioned downstream of the static mixing assembly and coupled to the static mixing assembly to receive the colored polymer stream. The spinning machine(s) may be configured to form the colored polymer stream into bulked continuous carpet filament having a tonal color effect.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional PatentApplication Ser. No. 62/559,443, filed Sep. 15, 2017, the entiredisclosure of which is hereby incorporated by reference in its entirety.

BACKGROUND

Currently, many different carpet designs are available. However, it isdifficult, using traditional manufacturing processes, tocost-effectively produce small, customized runs of broadloom carpetbecause doing so typically requires small amounts of BCF yarns to beproduced in dedicated colors. Producing small amounts of BCF yarns indedicated colors is typically expensive because changing a traditionalBCF production line from one color to another may require shutting downthe line and/or running the line to produce an undesired color (whichmay ultimately be discarded as waste) while the line is transitioningfrom one color to the next.

It is also currently difficult to produce a substantiallyuniform-looking “tonal” effect in broadloom carpets in which theindividual strands of BCF include multiple different tones of the samecolor or colors, and in which the various tones of the same color(s) aremaintained in the same or similar approximate proportions over thelength of the individual strands of BCF (e.g., so that the resultingcarpet includes an overall, uniform-appearing coloring comprisingdifferent tones of the same color(s)).

Accordingly, there is currently a need for improved processes forproducing small, customized runs of broadloom carpet, especially wherethe individual strands of BCF are colored to produce a tonal effect.There is a further need for processes that allow for creating differenttonal effects (which may, for example, be customized according tocustomer requests) and for manufacturing BCF for such carpet fromrecycled material, such as recycled plastic bottles.

SUMMARY

In various embodiments, a method of manufacturing bulked continuouscarpet filament having a tonal color effect from polyethyleneterephthalate (PET) using an extruder is provided. According to themethod, an extruder (e.g., a multi-screw extruder, such as an MRSmachine) at least partially melts the PET into a polymer melt and atleast partially purifies the polymer melt to create a polymer stream.The polymer stream enters a static mixing assembly having one or moreindividual static mixing elements (e.g., at least thirty individualstatic mixing elements) at an upstream end and exits at a downstreamend. One or more colorant ports positioned along a length of the staticmixing assembly provide colorant to the polymer stream at any of aplurality of different locations along the length of the static mixingassembly. In a particular embodiment, a plurality of colorant ports areprovided—each at different lengths from the downstream end of the staticmixing assembly, and a user may select which colorant port to injectcolorant through. After mixing the polymer stream with the colorantwithin the static mixing assembly, the polymer stream is formed intobulked continuous carpet filament having a tonal color effect. Inparticular embodiments, the tonal color effect varies based on whichcolorant port is selected to deliver the colorant into the polymerstream (e.g., because the colorant will generally mix with the polymerstream to a different extent based on the number of static mixingelements that the colorant/polymer mixture passes through).

So, according to a first embodiment of the invention, a method ofmanufacturing a bulked continuous carpet filament from polyethyleneterephthalate (PET) having a tonal color effect is provided, the methodcomprising the steps of:

-   -   providing an extruder;    -   using the extruder to at least partially melt the PET into a        polymer melt and at least partially purifying the polymer melt        to create a polymer stream;    -   providing a static mixing assembly comprising one or more        individual static mixing elements that are aligned to form a        central passageway for the polymer stream to pass through such        that the polymer stream enters an upstream end of the static        mixing assembly and exits a downstream end of the static mixing        assembly, and is mixed by the one or more individual static        mixing elements between the upstream end and the downstream end        of the static mixing assembly;    -   providing a plurality of colorant ports positioned along a        length of the static mixing assembly from the upstream end to        the downstream end such that each of the plurality of colorant        ports is configured to provide colorant to the polymer stream at        a different location along the length of the static mixing        assembly;    -   using the static mixing assembly to mix the polymer stream with        the colorant provided at a colorant port from a position of the        colorant port to the downstream end of the static mixing        assembly; and    -   after using the static mixing assembly to mix the polymer stream        with the colorant, forming the polymer stream into bulked        continuous carpet filament having a tonal color effect.

According to some embodiments, the method may further comprise the stepsof:

-   -   injecting the colorant into a colorant port proximate to the        downstream end of the static mixing assembly; and    -   receiving the polymer stream at a spinning machine from the        downstream end of the static mixing assembly having a tonal        color effect resulting from non-uniform mixing of the colorant        with the polymer stream within the static mixing assembly.

According to some embodiments, the colorant port may be positioned toinject colorant into the static mixing assembly two to four staticmixing elements from the downstream end of the static mixing assembly.

According to some embodiments, the colorant port may comprise a firstcolorant port, and the tonal color effect of the polymer stream receivedat the spinning machine resulting from the colorant injected into thefirst colorant port may comprise a first tonal color effect, and themethod may further comprise:

-   -   stopping the injection of the colorant into the first colorant        port; and    -   injecting the colorant into a second colorant port at a location        along the length of the static mixing assembly upstream of the        first colorant port to create a polymer stream having a second        tonal color effect that is less pronounced than the first tonal        color effect due to an increased mixing length from the second        colorant port to the downstream end of the static mixing        assembly as compared to a mixing length from the first colorant        port to the downstream end of the static mixing assembly.

According to some embodiments, the colorant port may comprise a firstcolorant port, and the method may further comprise:

-   -   stopping the injection of the colorant into the first colorant        port; and    -   injecting the colorant into a second colorant port at a location        along the length of the static mixing assembly proximate to the        upstream end of the static mixing assembly to substantially        thoroughly mix the polymer stream with the colorant to change        the tonal color effect of the polymer stream to a polymer stream        having a substantially uniform color.

According to some embodiments, the method may further comprise:

-   -   providing a plurality of colorant containers coupled to the        plurality of colorant ports; and    -   injecting a plurality of colorant into the polymer stream at the        plurality of locations along the length of the static mixing        assembly.

According to some embodiments, the plurality of colorant ports each maycomprise quick-disconnect coupling mechanisms configured to allow forthe installation and de-installation of a colorant container while thepolymer stream traverses through the static mixing assembly.

According to some embodiments, the method further may comprise splittingthe polymer stream into a plurality of individual polymer streamsdownstream from the extruder and the static mixing assembly may comprisea static mixing assembly for each of the plurality of individual polymerstreams such that each of the plurality of individual polymer streamsforms into bulked continuous carpet filament having a tonal coloreffect.

According to some embodiments, the extruder may be a multi-screwextruder.

According to some embodiments, the static mixing assembly may comprise asubstantially cylindrical housing encompassing the one or moreindividual static mixing elements.

According to some embodiments, the one or more individual static mixingelements may comprise at least thirty individual static mixing elements.

According to some embodiments, the one or more individual static mixingelements may comprise thirty-six to forty individual static mixingelements.

According to some embodiments, the one or more individual static mixingelements may comprise at least five individual static mixing elementsarranged consecutively in series, and the plurality of colorant portsmay comprise at least one colorant port corresponding to each of the atleast five individual static mixing elements.

According to some embodiments, the one or more individual static mixingelements may comprise at least ten individual static mixing elements,and the plurality of colorant ports may comprise at least one respectivecolorant port corresponding to each respective one of the at least tenindividual static mixing elements.

According to some embodiments, the one or more individual static mixingelements may comprise at least two individual static mixing elementsarranged in series, wherein each of the at least two individual staticmixing elements comprise:

-   -   a housing; and    -   one or more mixing bars or one or more helical mixing elements.

According to a second embodiment of the invention, a system formanufacturing a bulked continuous carpet filament from polyethyleneterephthalate (PET) having a tonal color is provided. In thisembodiment, the system comprises:

-   -   an extruder configured to at least partially melt the PET into a        polymer melt and at least partially purify the polymer melt to        create a polymer stream;    -   a static mixing assembly positioned downstream of the extruder        and fluidly coupled to the extruder to receive the polymer        stream and to create a colored polymer stream, each of the        static mixing assemblies comprising: (a) a housing, and (b) one        or more individual static mixing elements disposed within the        housing such that the polymer stream enters an upstream end of        the static mixing assembly and exits a downstream end of the        static mixing assembly;    -   a plurality of colorant ports along a length of the static        mixing assembly from the upstream end to the downstream end such        that each of the plurality of colorant ports is configured to        provide colorant to the polymer stream at a different location        along the length of the static mixing assembly; and    -   one or more spinning machines positioned downstream of the        static mixing assembly and fluidly coupled to the static mixing        assembly to receive the colored polymer stream, the one or more        spinning machines configured to form the colored polymer stream        into bulked continuous carpet filament having a tonal color        effect.

According to some embodiments, the plurality of colorant ports maycomprise:

-   -   a first colorant port positioned proximate to the upstream end        of the static mixing assembly such that colorant injected        through the first colorant port is uniformly mixed over the        length of the static mixing assembly to create a        uniformly-colored characteristic of the colored polymer stream;        and    -   a second colorant port positioned downstream of the first        colorant port such that colorant injected through the second        colorant port mixes with the polymer stream for a distance        shorter than the length of the static mixing assembly to create        a tonal effect characteristic of the colored polymer stream.

According to some embodiments, the system further may comprise one ormore colorant containers coupled to the one or more colorant ports.

According to some embodiments, the one or more colorant containers arecoupled to the one or more colorant ports via quick-disconnect couplingmechanisms configured to allow for the installation and de-installationof a colorant container while the polymer stream traverses through thestatic mixing assembly.

According to some embodiments, the static mixing assembly may comprise aplurality of static mixing assemblies, each static mixing assemblyreceiving an individual polymer stream of a plurality of individualpolymer streams split from the polymer stream downstream of theextruder.

According to some embodiments, one or more colorant ports may bepositioned to inject colorant into the static mixing assembly two tofour static mixing elements from the downstream end of the static mixingassembly.

According to some embodiments, one or more colorant ports may bepositioned to inject colorant into the static mixing assembly atdifferent positions around a circumference of the static mixingassembly.

The system according the second aspect of the invention may be fit for,and hence may be used to execute a method according to the first aspectof the invention.

The methods and systems according to various embodiments of theinvention may provide the advantage of enabling unique carpet designs tobe made (e.g., at a reasonable cost). The methods and systems may havethe further advantage of allowing for the efficient production oftonally-colored BCF in small batches (which may be customized, forexample, according to a particular customer's preferences), which mayallow for the production of small quantities of carpet to be producedhaving unique, potentially customized, tonal coloring.

Accordingly, methods and systems according to various embodiments of theinvention may have the further advantage of producing BCF for use inbroadloom carpets that results in a substantially uniform-looking“tonal” effect in the carpets. In various embodiments, the individualstrands of BCF include multiple different tones of the same color orcolors, and the various tones of the same color or colors may bemaintained in the same or similar approximate proportions over thelength of the individual strands of BCF (e.g., so that the resultingcarpet includes an overall, uniform-appearing coloring comprisingdifferent tones of the same color or colors). Various embodiments allowfor the production of BCF for use in such carpets from recycledmaterial, such as recycled plastic bottles and/or virgin material.

The independent and dependent claims below set out particular andpreferred features of the invention. Features from the dependent claimsmay be combined with features of the independent or other dependentclaims, and/or with features set out in the description above and/orhereinafter as appropriate.

The above and other characteristics, features and advantages of thepresent invention will become apparent from the following detaileddescription, taken in conjunction with the accompanying drawings, whichillustrate, by way of example, the principles of various embodiments ofthe invention. This description is given for the purposes of exampleonly, without limiting the scope of the invention. The reference figuresnumbers referenced below refer to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Having described various embodiments in general terms, reference willnow be made to the accompanying drawings, which are not necessarilydrawn to scale, and wherein:

FIG. 1 depicts a high-level overview of a manufacturing process forproducing and coloring bulked continuous filament.

FIG. 2 depicts a process flow, according to a particular embodiment, foradding a colorant to a stream of molten polymer downstream from a firstextruder.

FIG. 3 is a perspective view of an MRS extruder that is suitable for useas the first extruder of FIG. 2.

FIG. 4 is a cross-sectional view of an exemplary MRS section of the MRSextruder of FIG. 2.

FIG. 5 is a cross-sectional end view of dispersion of a colorant in astream of molten polymer prior to passing through the one or more staticmixing assemblies shown in FIG. 2.

FIG. 6 is a cross-sectional end view of dispersion of a colorant in astream of molten polymer following passing through the one or morestatic mixing assemblies shown in FIG. 2.

FIG. 7 is a cross-sectional end view of the exemplary one of the one ormore static mixing elements of FIG. 2, according to a particularembodiment.

FIG. 8 is a side view of eight of the exemplary static mixing elementsof FIG. 7 coupled to one another to form a static mixing assembly.

FIG. 9 is a perspective view of an exemplary helical static mixingassembly according to a particular embodiment.

FIG. 10 is a perspective cutaway view of the helical static mixingassembly of FIG. 9 showing four helical static mixing elements.

FIG. 11 depicts a process flow, according to a particular embodiment,for adding various colorants to several streams of molten polymerdownstream from a first extruder.

FIG. 12 depicts a process flow, according to another embodiment, foradding various colorants to several streams of molten polymer downstreamfrom a first extruder.

FIG. 13 depicts a side view of a static mixing assembly havingindividual static mixing elements coupled to one another to form astatic mixing assembly and one or more colorant ports coupled to thestatic mixing assembly.

FIG. 14 depicts a high level overview of a manufacturing process forproducing and coloring a bulked continuous filament with a tonal coloreffect.

Within the figures, the same reference signs refer to the same, similaror analogous elements within the various figures.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Various embodiments will now be described in greater detail. It shouldbe understood that the invention may be embodied in many different formsand should not be construed as limited to the embodiments set forthherein. Rather, these embodiments are provided so that this disclosurewill be thorough and complete, and will fully convey the scope of theinvention to those skilled in the art. Like numbers refer to likeelements throughout.

It is noted that the term “comprising”, as used in the claims, shouldnot be interpreted as being restricted to the means listed thereafter;this term does not exclude other elements or steps. The term“comprising” is thus to be interpreted as specifying the presence of thestated features, steps or components as referred to, but does notpreclude the presence or addition of one or more other features, stepsor components, or groups thereof.

Throughout this specification, references to “one embodiment” or “anembodiment” are made. Such references indicate that a particularfeature, described in relation to the embodiment, is included in atleast one embodiment of the present invention. Thus, appearances of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout this specification are not necessarily all referring to thesame embodiment, though they could.

Furthermore, the particular features or characteristics described hereinmay be combined in any suitable manner in one or more embodiments, aswould be apparent to one of ordinary skill in the art.

Overview

New processes for producing and coloring fiber from recycled polymer(e.g., recycled PET polymer) and virgin polymer (e.g., virgin PETpolymer) are described below. In various embodiments, these newprocesses may include, for example: (1) extruding a polymer (e.g., suchas PET) using a primary extruder; (2) adding a colorant to the extrudedpolymer downstream from the primary extruder; (3) using one or morestatic mixing elements (e.g., up to thirty six static mixing elements ormore) to substantially uniformly mix the extruded polymer and the addedcolorant; and (4) using a spinning machine to spin the uniformly-mixedextruded polymer and added colorant into bulked continuous filament(e.g., carpet yarn) that has a color that is based on the addedcolorant. The process described herein may, for example, reduce anamount of waste related to changing a color of bulked continuousfilament produced using a particular extruder when switching to adifferent colorant.

In various embodiments, the primary extruder comprises a multi-rotatingscrew extruder (MRS extruder). In particular embodiments, the processfurther comprises: (1) splitting the molten polymer stream extruded fromthe primary extruder into a plurality of polymer streams (e.g., up tosix polymer streams), each of the plurality of polymer streams having anassociated spinning machine; (2) adding a colorant to each split polymerstream; (3) using one or more static mixing assemblies for each splitpolymer stream to substantially uniformly mix each split polymer streamand its respective colorant; and (4) spinning each polymer stream withits substantially uniformly mixed colorant into bulked continuousfilament using the respective spinning machine. In such embodiments, aprocess for producing and coloring bulked continuous filament mayutilize a single primary extruder to produce a plurality of differentcolored filaments (e.g., carpet yarn).

In various embodiments, this new process may, for example: (1) produceless waste than other processes when producing or changing a color ofbulked continuous filament produced using a particular extruder; (2)facilitate the production of small batches of particular colors offilament (e.g., for use in rugs or less popular colors of carpet) at arelatively low cost; (3) increase a number of simultaneous filamentcolors that a single extruder can produce; and (4) etc. In at least oneembodiment, the improved process results in reduction of waste of up toabout 4,000 pounds of fiber when switching from a first color to asecond color (e.g., by adding the colorant downstream from the primaryextruder rather than upstream).

In particular embodiments, a smaller number of static mixing elementsthan described above (e.g., any suitable number between 5 and 20 staticmixing elements) may be used to produce a tonal coloring effect withinthe BCF. This tonal coloring effect may reflect a non-uniform mixing ofcolorant into the polymer stream.

The tonal effect may be produced due to the fact that the liquidcolorant would only be partially further mixed into the polymer streameach time it passes through a single static mixing element. So each timea segment of the colorant/polymer stream mixture passes through anotherstatic mixing element, the mixture will become slightly more uniform.After passing through a certain number of static mixing elements (e.g.,30), the colorant/polymer mixture will be substantially uniform. Asnoted above, the colorant/polymer stream mixture is passed through anumber of static mixing elements that is selected to produce asubstantially uniform, partial mixture of colorant and polymer. Theresult is a fiber with a consistent, tonal coloring effect. In variousembodiments, the system is adapted to be easily reconfigured (e.g.,through the use of quick-release connectors spaced at different pointsalong the length of a series of static mixing elements) to injectcolorant so that it passes through the desired number of static mixingelements before exiting the series of static mixing elements. This mayallow a user to easily reconfigure the machine to produce BCF withdifferent types of tonal coloring.

More Detailed Discussion

FIG. 1 depicts a high-level overview of BCF manufacturing process 100for producing and coloring BCF (bulked continuous filament), forexample, for use in the production of carpet and other products. Themethod of manufacturing bulked continuous filament—as indicated in FIG.1 by 100, may, according to a particular embodiment, in general bebroken down into four steps indicated as 102, 104, 106 and 108: (1)passing PET (e.g., or other polymer flakes) through an extruder thatmelts the flakes and purifies the resulting PET polymer (Step 102); (2)optionally splitting the extruded polymer melt into a plurality of meltstreams and adding a colorant to each of the plurality of melt streams(Step 104); (3) using one or more static mixing assemblies tosubstantially uniformly mix each of the plurality of melt streams withits respective added colorant (Step 106); and (4) feeding each of thesubstantially uniformly mixed and colored plurality of melt streams intoa respective spinning machine that turns the polymer into filament foruse in manufacturing carpets (Step 108), thereby ending the method ofmanufacturing bulked continuous filaments—as indicated in FIG. 1 by 110.These four steps are described in greater detail below.

Step 1: Using an Extrusion System to Melt and Purify PET

In various embodiments, the step of using an extrusion system to meltand purify PET (e.g., PET flakes and/or pellets) comprises: (A)preparing the PET for extrusion; and (B) using a suitable extruder tomelt and purify the PET.

Preparing the PET for Extrusion

In particular embodiments, the step of preparing the PET for extrusionmay vary based on a source of the PET. For example, in variousembodiments, the process may utilize: (1) virgin PET (e.g., virgin PETpellets); (2) recycled PET (e.g., recycled PET flakes ground fromrecycled PET bottles and other suitable sources); and/or (3) acombination of virgin and recycled PET. In various embodiments in whichthe process utilizes recycled PET, the step of preparing the PET forextrusion may include sorting, grinding, washing and other stepsdesigned to remove any impurities from the recycled PET prior toextrusion. These other PET preparation steps may, for example, beunnecessary in embodiments of the process that utilize virgin PET.Because using recycled PET in the process described herein maycontribute to even further costs savings to those associated with areduction in waste due to colorant changing, the process will bedescribed below particularly with respect to recycled PET.

In a particular embodiment, preparing the PET for extrusion may includepreparing flakes of PET polymer from post-consumer bottles or othersources of recycled PET. An exemplary process for preparingpost-consumer bottles for use in the production of bulked continuousfilament is described in U.S. Pat. No. 8,597,553 B1, entitled “Systemsand Methods for Manufacturing Bulked Continuous Filament” and publishedon Dec. 3, 2013, which is hereby incorporated herein in its entirety.Generally speaking, the step of preparing flakes of PET polymer frompost-consumer bottles may comprise, for example: (A) sortingpost-consumer PET bottles and grinding the bottles into flakes; (B)washing the flakes; and (C) identifying and removing any impurities orimpure flakes.

Sorting Post-Consumer PET Bottles and Grinding the Bottles into Flakes

In particular embodiments, bales of clear and mixed colored recycledpost-consumer (e.g., “curbside”) PET bottles (or other containers)obtained from various recycling facilities make-up the post-consumer PETcontainers for use in the process. In other embodiments, the source ofthe post-consumer PET containers may be returned ‘deposit’ bottles(e.g., PET bottles whose price includes a deposit that is returned to acustomer when the customer returns the bottle after consuming thebottle's contents). The curbside or returned “post-consumer” or“recycled” containers may contain a small level of non-PET contaminates.The contaminants in the containers may include, for example, non-PETpolymeric contaminants (e.g., PVC, PLA, PP, PE, PS, PA, etc.), metal(e.g., ferrous and non-ferrous metal), paper, cardboard, sand, glass orother unwanted materials that may find their way into the collection ofrecycled PET. The non-PET contaminants may be removed from the desiredPET components, for example, through one or more of the variousprocesses described below.

In particular embodiments, smaller components and debris (e.g.,components and debris greater than 2 inches in size) are removed fromthe whole bottles via a rotating trammel. Various metal removal magnetsand eddy current systems may be incorporated into the process to removeany metal contaminants. Near Infra-Red optical sorting equipment such asthe NRT Multi Sort IR machine from Bulk Handling Systems Company ofEugene, Oreg., or the Spyder IR machine from National RecoveryTechnologies of Nashville, Tenn., may be utilized to remove any loosepolymeric contaminants that may be mixed in with the PET flakes (e.g.,PVC, PLA, PP, PE, PS, and PA). Additionally, automated X-ray sortingequipment such as a VINYLCYCLE machine from National RecoveryTechnologies of Nashville, Tenn. may be utilized to remove remaining PVCcontaminants.

In particular embodiments, the sorted material is taken through agranulation step (e.g., using a 50B Granulator machine from CumberlandEngineering Corporation of New Berlin, Wis.) to size reduce (e.g.,grind) the bottles down to a size of less than one half of an inch. Invarious embodiments, the bottle labels are removed from the resultant“dirty flake” (e.g., the PET flakes formed during the granulation step)via an air separation system prior to entering the wash process.

Washing the Flakes

In particular embodiments, the “dirty flake” is then mixed into a seriesof wash tanks. As part of the wash process, in various embodiments, anaqueous density separation is utilized to separate the olefin bottlecaps (which may, for example, be present in the “dirty flake” asremnants from recycled PET bottles) from the higher specific gravity PETflakes. In particular embodiments, the flakes are washed in a heatedcaustic bath to about 190 degrees Fahrenheit. In particular embodiments,the caustic bath is maintained at a concentration of between about 0.6%and about 1.2% sodium hydroxide. In various embodiments, soapsurfactants as well as defoaming agents are added to the caustic bath,for example, to further increase the separation and cleaning of theflakes. A double rinse system then washes the caustic from the flakes.

In various embodiments, the flake is centrifugally dewatered and thendried with hot air to at least substantially remove any surfacemoisture. The resultant “clean flake” is then processed through anelectrostatic separation system (e.g., an electrostatic separator fromCarpco, Inc. of Jacksonville, Fla.) and a flake metal detection system(e.g., an MSS Metal Sorting System) to further remove any metalcontaminants that remain in the flake. In particular embodiments, an airseparation step removes any remaining label from the clean flake. Invarious embodiments, an electro-optical flake sorter based at least inpart on Raman technology (e.g., a Powersort 200 from UnisensorSensorsysteme GmbH of Karlsruhe, Germany) performs the final polymerseparation to remove any non-PET polymers remaining in the flake. Thisstep may also further remove any remaining metal contaminants and colorcontaminants.

In various embodiments, the combination of these steps deliverssubstantially clean (e.g., clean) PET bottle flake comprising less thanabout 50 parts per million PVC (e.g., 25 ppm PVC) and less than about 15parts per million metals for use in the downstream extrusion processdescribed below.

Identifying and Removing Impurities and Impure Flakes

In particular embodiments, after the flakes are washed, they are feddown a conveyor and scanned with a high-speed laser system 300. Invarious embodiments, particular lasers that make up the high-speed lasersystem 300 are configured to detect the presence of particularcontaminates (e.g., PVC or Aluminum). Flakes that are identified as notconsisting essentially of PET may be blown from the main stream offlakes with air jets. In various embodiments, the resulting level ofnon-PET flakes is less than 25 ppm.

In various embodiments, the system is adapted to ensure that the PETpolymer being processed into filament is substantially free of water(e.g., entirely free of water). In a particular embodiment, the flakesare placed into a pre-conditioner for between about 20 and about 40minutes (e.g., about 30 minutes) during which the pre-conditioner blowsthe surface water off of the flakes. In particular embodiments,interstitial water remains within the flakes. In various embodiments,these “wet” flakes (e.g., flakes comprising interstitial water) may thenbe fed into an extruder (e.g., as described below), which includes avacuum setup designed to remove—among other things—the interstitialwater that remains present in the flakes following the quick-dryingprocess described above.

Using an Extrusion System to Melt and Purify PET Flakes

FIG. 2 depicts an exemplary process flow for producing BCF with an addedcolorant according to particular embodiments. As shown in FIG. 2, invarious embodiments, a suitable primary extruder 202 is used to melt andpurify PET 200, such as any suitable PET 200 prepared in any mannerdescribed above. In a particular embodiment, the primary extruder 202comprises any suitable extruder such as, for example, a MultipleRotating Screw (“MRS”) extruder, a twin screw extruder, a multiple screwextruder, a planetary extruder, or any other suitable extrusion system.An exemplary MRS Extruder 400 is shown in FIGS. 3 and 4. A particularexample of such an MRS extruder is described in U.S. Published PatentApplication 2005/0047267, entitled “Extruder for Producing MoltenPlastic Materials”, which was published on Mar. 3, 2005, and which ishereby incorporated herein by reference.

As may be understood from FIGS. 3 and 4, in particular embodiments, theMRS extruder includes a first single-screw extruder section 410 forfeeding material into an MRS section 420 and a second single-screwextruder section 440 for transporting material away from the MRSsection.

As may be understood from FIG. 3, in various embodiments, PET is firstfed through the MRS extruder's first single-screw extruder section 410,which may, for example, generate sufficient heat (e.g., via shearing) toat least substantially melt (e.g., melt) the wet flakes.

The resultant polymer melt (e.g., comprising the melted PET), in variousembodiments, is then fed into the extruder's MRS section 420, in whichthe extruder separates the melt flow into a plurality of differentstreams (e.g., 4, 5, 6, 7, 8, or more streams) through a plurality ofopen chambers. FIG. 4 shows a detailed cutaway view of an MRS Section420 according to a particular embodiment. In particular embodiments,such as the embodiment shown in this figure, the MRS Section 420separates the melt flow into eight different streams, which aresubsequently fed through eight satellite screws 425A-H. As may beunderstood from FIG. 3, in particular embodiments, these satellitescrews are substantially parallel (e.g., parallel) to one other and to aprimary screw axis of the MRS Machine 400.

As shown in FIG. 4, in particular embodiments: (1) the satellite screws425A-H are arranged within a single screw drum 428 that is mounted torotate about its central axis; and (2) the satellite screws 425A-H areconfigured to rotate in a direction that is opposite to the direction inwhich the single screw drum rotates 428. In various other embodiments,the satellite screws 425A-H and the single screw drum 428 rotate in thesame direction. In particular embodiments, the rotation of the satellitescrews 425A-H is driven by a ring gear. Also, in various embodiments,the single screw drum 428 rotates about four times faster than eachindividual satellite screw 425A-H. In certain embodiments, the satellitescrews 425A-H rotate at substantially similar (e.g., the same) speeds.

In various embodiments, as may be understood from FIG. 4, the satellitescrews 425A-H are housed within respective extruder barrels, which may,for example be about 30% open to the outer chamber of the MRS section420. In particular embodiments, the rotation of the satellite screws425A-H and single screw drum 428 increases the surface exchange of thepolymer melt (e.g., exposes more surface area of the melted polymer tothe open chamber than in previous systems). In various embodiments, theMRS section 420 creates a melt surface area that is, for example,between about twenty and about thirty times greater than the meltsurface area created by a co-rotating twin screw extruder. In aparticular embodiment, the MRS section 420 creates a melt surface areathat is, for example, about twenty-five times greater than the meltsurface area created by a co-rotating twin screw extruder.

In various embodiments, the MRS extruder's MRS Section 420 is fittedwith a vacuum pump that is attached to a vacuum attachment portion 422of the MRS section 420 so that the vacuum pump is in communication withthe interior of the MRS section via a suitable opening 424 in the MRSsection's housing. In still other embodiments, the MRS Section 420 isfitted with a series of vacuum pumps. In particular embodiments, thevacuum pump is configured to reduce the pressure within the interior ofthe MRS Section 420 to a pressure that is between about 0.5 millibarsand about 25 millibars. In particular embodiments, the vacuum pump isconfigured to reduce the pressure in the MRS Section 420 to less thanabout 5 millibars (e.g., about 1.8 millibars or less). The low-pressurevacuum created by the vacuum pump in the MRS Section 420 may remove, forexample: (1) volatile organics present in the melted polymer as themelted polymer passes through the MRS Section 420; and/or (2) at least aportion of any interstitial water that was present in the wet flakeswhen the wet flakes entered the MRS Extruder 400. In variousembodiments, the low-pressure vacuum removes substantially all (e.g.,all) of the water and contaminants from the polymer stream.

In some embodiments, after the molten polymer is run the through themulti-stream MRS Section 420, the streams of molten polymer arerecombined and flow into the MRS extruder's second single screw section440. In particular embodiments, passage through the low pressure MRSSection 420 purifies the recycled polymer melt (e.g., by removing thecontaminants and interstitial water) and makes the recycled polymersubstantially structurally similar to (e.g., structurally the same as)pure virgin PET polymer. In particular embodiments, the resultingpolymer is a recycled PET polymer (e.g., obtained 100% frompost-consumer PET products, such as PET bottles or containers) having apolymer quality that is suitable for use in producing PET carpetfilament using substantially only (e.g., only) PET from recycled PETproducts.

Step 2: Add a Colorant to the Polymer Melt Downstream from the PrimaryExtruder

In particular embodiments, after the recycled PET polymer (e.g., orvirgin PET) has been extruded and purified by the above-describedextrusion process, a colorant is added to the resultant polymer melt. Asshown in FIG. 2, Colorant A 204 may be added to the polymer melt using asuitable secondary extruder 206. In various embodiments, the secondaryextruder 206 may include any suitable extruder such as for example, anysuitable single-screw extruder or other extruder described herein (e.g.,a twin screw extruder, a multiple screw extruder, a planetary extruder,or any other suitable extrusion system). In particular embodiments, asuitable secondary extruder 206 may include, for example, an HPE-150Horizontal Extruder manufactured by David-Standard, LLC of Pawcatuck,Conn.

In particular embodiments, Colorant A 204 may comprise pelletized colorconcentrate which the secondary extruder 206 is configured to at leastpartially melt prior to adding Colorant A 204 to the polymer melt. Invarious other embodiments, Colorant A 204 may comprise other additivessuch as, for example, a carrier resin which may aid in binding thecolorant to the polymer. In other embodiments, Colorant A 204 mayinclude any suitable liquid colorant which may be pumped into thepolymer melt using any suitable pump (e.g., in lieu of using a secondaryextruder 206 and pelletized color concentrate).

In various embodiments, the process may further include monitoring anamount of throughput (e.g., polymer output) from the primary extruder202 in order to determine an appropriate amount of letdown (e.g., anappropriate let down ratio) such that a proper amount of Colorant A 204is added to the polymer melt downstream from the primary extruder 202.In various embodiments, a desirable letdown ratio may include a letdownratio of between about two percent and about eight percent. In otherembodiments, the letdown ratio may include any other suitable letdownratio (e.g., one percent, two percent, three percent, four percent, fivepercent, six percent, seven percent, etc.). In particular embodiments,the letdown ratio may vary based on a desired color of bulked continuousfilament ultimately produced using the process (e.g., up to about twentypercent).

In various embodiments, adding the colorant 204 downstream of theprimary extruder 202 may save on waste during color changeover. Forexample, when switching between producing bulked continuous filament ofa first color to producing bulked continuous filament of a second color,it is necessary to change the colorant 204 added to the polymer melt(e.g., from a first colorant that would result in bulked continuousfilament of the first color to a second colorant that would result inbulked continuous filament of the second color). As may be understood byone skilled in the art, after switching from adding the first colorantto the polymer melt to adding the second colorant to the polymer melt,residual first colorant may remain in in the system between the point inthe process at which the colorant is added and the spinning machine 212.For example, residual first colorant may remain in the secondaryextruder 206, the one or more static mixing assemblies 208, or any otherphysical mechanism used in the process (such as any mechanism shown inFIG. 2) or any piping or tubing which connects the various components ofthe system.

As may be understood by one skilled in the art, after running theprocess with the second colorant for a suitable amount of time, thebulked continuous filament produced by the process will eventually be ofthe second, desired color (e.g., because the first colorant willeventually be substantially flushed out the system). Between the pointat which there is a changeover in adding the second colorant to theprocess rather than the first colorant and the point at which theprocess begins to produce the desired color of bulked continuousfilament, the process will produce some waste bulked continuous filamentthat is of an undesired color (e.g., due at least in part to theresidual first colorant).

In various embodiments, the waste bulked continuous filament producedusing the process described herein may be considerably lower than wastebulked continuous filament produced during color changeovers using otherprocesses (e.g., such as other processes in which colorant is added toPET prior to extrusion in a primary extruder such as an MRS extruder).For example, in various embodiment, the process described herein maylimit waste bulked continuous filament to an amount of bulked continuousfilament produced when running a single package of colorant (e.g., ofthe second colorant), which may, for example, result in less than about100 pounds of waste. In particular embodiments, reducing waste may leadto cost savings in the production of bulked continuous filament.

Step 3: Use One or More Static Mixing Assemblies to Mix Polymer Meltwith Added Colorant

In particular embodiments, following the addition of Colorant A 204 tothe stream of molten polymer, the process includes the use of one ormore static mixing assemblies 208 (e.g., one or more static mixingelements) to mix and disperse Colorant A 204 throughout the polymerstream. As may be understood by one skilled in the art, due in part tothe viscosity of the polymer stream (e.g., polymer melt), when a dye orother colorant is added to the polymer stream, the dye and the streammay not mix. In various embodiments, the flow of the polymer melt issubstantially laminar (e.g., laminar) which may, for example, furtherlead to a lack of mixing. FIG. 5 depicts a cross section view of a pipe500 containing a polymer melt 510 into which a liquid colorant 520 hasbeen added. As shown in this Figure, the liquid colorant 520 has notmixed with the polymer melt 510. Generally speaking, the unmixed polymermelt 510 and colorant 520 may not be suitable for forming into bulkedcontinuous filament (e.g., because the resulting filament may not have aconsistent, uniform color). FIG. 6 depicts the pipe 500 of FIG. 5 inwhich the liquid colorant 520 and the polymer melt 510 have beensubstantially thoroughly (e.g., uniformly) mixed into a colored meltstream 530. This substantially uniform mixing, in various embodiments,is achieved through the use of the one or more static mixing assemblies208 as shown in FIG. 2. Generally speaking, this uniformly mixed coloredmelt stream 530 shown in FIG. 5 may be far more suitable for producinguniformly colored bulked continuous filament.

FIG. 7 depicts an exemplary static mixing element 700 which may, invarious embodiments, be utilized in the achievement of substantiallyuniform (e.g., uniform) mixing of the polymer melt and the addedcolorant (e.g., Colorant A 204 from FIG. 2). As may be understood fromthis Figure, a static mixing element 700 may comprise a housing 702(e.g., a substantially circular or cylindrical housing) and be insertedinto a pipe or other housing (e.g., incorporated into a pipe or otherhousing). In the embodiment shown in this Figure, the static mixingelement 700 comprises a plurality of mixing bars 704 disposed within thehousing 702. In particular embodiments, the static mixing element 700creates mixing by directing two or more viscous materials to follow thegeometric structure of the mixing bars 704 disposed within the housing702 that continuously divide and recombine the flow. In variousembodiments, a very high degree of mixing may be achieved over a shortlength of static mixing elements. In particular embodiments, the staticmixing element 700 comprises no moving parts and is made of any suitablematerial such as, for example high strength heat treated stainlesssteel, a suitable plastic, or any other suitable material.

In particular embodiments, the static mixing assemblies 208 shown inFIG. 2 comprise any suitable static mixing element, such as, forexample, a Stamixco GXR 40/50 or GXR 52/60 made by Stamixco LLC ofBrooklyn, N.Y. A suitable mixing element for use as or within a staticmixing assembly is described in U.S. Pat. No. 8,360,630 B2, entitled“Mixing Elements for a Static Mixer and Process for Producing Such aMixing Element” and published on Jan. 29, 2013, which is herebyincorporated herein in its entirety. In other embodiments, the one ormore static mixing assemblies 208 may comprise any other suitable staticmixing element having a suitable arrangement of mixing bars fordispersing the colorant throughout the polymer melt. In particularembodiments, the one or more static mixing assemblies 208 comprise aplurality of individual static mixing elements 700 such as is shown inFIG. 8. FIG. 8 depicts eight static mixing elements 700 a-h coupled toone another to form a static mixing assembly 208. In other embodiments,the static mixing assemblies 208 may comprise any suitable number ofindividual static mixing elements 700 (e.g., up to 36 or 40 individualstatic mixing elements). In particular embodiments, the individualstatic mixing elements 700 may be oriented in any suitable directionrelative to one another (e.g., oriented randomly relative to one anotherwhen coupled to one another as shown in FIG. 8).

In various other embodiments, the static mixing assemblies 208 maycomprise a suitable number of static mixing elements comprising one ormore suitable helical mixing elements. FIG. 9 depicts an exemplaryhelical static mixing assembly 900 comprising a substantiallycylindrical (e.g., cylindrical) housing 902 in which at least onehelical mixing element 904 is disposed). As shown in this Figure, the atleast one helical mixing element 904 defines a leading edge 906 thatextends between opposing interior portions of the cylindrical housing(e.g., along a diameter of the cylindrical housing). In variousembodiments, the leading edge 906 is substantially planar (e.g., linear)and has any suitable thickness. As may be understood from this Figure,the leading edge 906 may divide (e.g., bisect) a polymer melt flowinginto the helical static mixing assembly 900 into two streams (e.g., afirst stream on a first side of the leading edge 906 and a second streamon a second side). In particular embodiments, the leading edge maydivide the flow into substantially equal streams as material passes thehelical mixing element 904.

FIG. 10 depicts the helical static mixing assembly 900 of FIG. 9 in acutaway view that shows four helical mixing elements 904 disposed withinthe housing 902. As may be further understood from FIG. 10, eachindividual helical mixing element 904 (e.g., helical mixing element 904a) comprises a substantially rectangular (e.g., rectangular) platedefining a leading edge 906 a and a trailing edge 908 a that has beentwisted about 180 degrees (e.g., 180 degrees). As shown in this Figure,the leading edge 906 a and trailing edge 908 a are substantiallyparallel (e.g., parallel) to one another and the helical mixing element904 a extends between the leading edge 906 a and trailing edge 908 a ina helical pattern. Although in the embodiment shown in this Figure, thehelical mixing element 904 a is shown having a twist of 180 degreesbetween the leading edge 906 a and trailing edge 908 a, it should beunderstood that in various other embodiments, each individual helicalmixing element 904 may comprise any other suitable helical shape orportion thereof. For example, in particular embodiments, the helicalmixing element 904 may comprise a substantially rectangular platedefining a leading edge 906 and a trailing edge 908 that has beentwisted any other suitable amount between zero and 360 degrees (e.g., 45degrees, 90 degrees, 270 degrees, etc.) In still other embodiments, thehelical mixing element 904 may have any suitable length relative to itsdiameter.

As may be further understood from FIG. 10, in various embodiments, eachparticular helical mixing element 904 a-d is disposed within the housing902 at an angle to an adjacent helical mixing element 904. For example,helical mixing element 904 a is disposed such that a trailing edge 908 aof helical mixing element 904 a forms an angle with the leading edge 906b of helical mixing element 906 b. In particular embodiments, thetrailing edge 908 a and leading edge 906 b of adjacent helical mixingelements 904 may form any suitable angle with one another. In particularembodiments, the trailing edge 908 a and leading edge 906 b of adjacenthelical mixing elements 904 may form an angle of between about zerodegrees and about ninety degrees with one another. In particularembodiments, the trailing edge 908 a and leading edge 906 b of adjacenthelical mixing elements 904 may at least partially abut one another andbe substantially co-facing (e.g., co-facing). In particular embodiments,the trailing edge 908 a and leading edge 906 b of adjacent helicalmixing elements 904 may form a particular angle between one another(e.g., zero degrees, ninety degrees, forty-five degrees, or any othersuitable angle). A suitable helical static mixing assembly for use inthe above-described process may include, for example, the any suitablehelical static mixing assembly manufactured by JLS International ofCharlotte, N.C.

It should be understood that for the purposes of this disclosure, astatic mixing assembly 208 may be configured in any desired arrangementto provide a desired number of one or more individual mixing elements toa polymer stream. For example, a static mixing assembly 208 may includea single mixing element within a single housing with one or more mixingbars 704 and/or one or more helical mixing elements 904 disposed withinthe housing. Alternatively, the static mixing assembly 208 may includemultiple static mixing elements positioned in series within a singlehousing. According to yet another alternative embodiment, the staticmixing assembly 208 may include a plurality of static mixing elements,each having their own respective housing positioned in series adjacentto one another. In this embodiment, the plurality of static mixingelements are collectively considered the static mixing assembly 208. Forexample, in particular embodiments, the static mixing assembly 208comprises up to thirty-six individual static mixing elements (e.g.,thirty-six static mixing elements, thirty-four static mixing elements,etc.). In still other embodiments, the static mixing assembly 208comprises any other suitable number of static mixing elements sufficientto substantially uniformly (e.g., homogeneously) mix the molten polymerwith the added colorant (e.g., to substantially uniformly mix the moltenpolymer and the added colorant into a colored melt stream 530 as shownin FIG. 6). This may include, for example, up to 40 static mixingelements, or any other suitable number).

In particular embodiments, the one or more static mixing assemblies 208may comprise any suitable combination of static mixing elements such as,for example, any suitable break down of the static mixing element 700shown in FIG. 7 and the helical static mixing assembly 900 and/orhelical mixing elements 904 shown in FIGS. 9 and 10. For example, in aparticular embodiment, the static mixing assemblies 208 may comprisethirty-six helical mixing elements 904. In other embodiments, the staticmixing assemblies 208 may comprise thirty-six static mixing elements 700from FIG. 7. In various embodiments, the static mixing assemblies 208may comprise any suitable number of alternating static mixing elements700 shown in FIG. 7 and helical mixing elements 904 shown in FIGS. 9 and10. In various other embodiments, the static mixing assemblies 208 maycomprise up to a total of forty (e.g., thirty-six), or more, individualstatic mixing elements 700 shown in FIG. 7 and helical mixing elements904 shown in FIGS. 9 and 10. In such embodiments, the static mixingelements 700 from FIG. 7 and the helical mixing elements 904 may bearranged in any suitable order (e.g., a specific order, a random order,a pattern such as a repeating pattern, etc.).

Creating a Tonal Color in Polymer Melt

According to various embodiments, it may be desirable to create BCF foruse in the production of carpet and other products that is not uniformin color. Specifically, it may be desirable to create BCF that has atonal color effect. For the purposes of this disclosure, BCF having atonal color effect may include BCF having any color that is not uniform,such as BCF that includes different shades of the same color (e.g., withgradual changes between one shade to another). Conventionally, tonalcolor effects may be created using one or more yarns or filaments havingone dark end and one light end, which are twisted together to create atonal yarn. However, using the concepts and technologies describedherein, a tonal color effect may be created using a single yarn, withoututilizing the conventional twisting process.

According to one embodiment, the tonal effect characteristic of thepolymer stream and resulting BCF product may be created using a smallernumber of static mixing elements (individual static mixing elements 700or helical mixing elements 904) as compared to the at least thirtyindividual static mixing elements utilized to create the uniformly mixedand uniformly colored polymer streams described above. For example,according to one implementation, a smaller number of individual staticmixing elements 700 or helical static mixing elements 904 (e.g., anydiscrete number less than thirty) may be used to create the staticmixing assemblies 208 of FIG. 2. By using a relatively small number ofindividual static mixing elements, in various embodiments, the colorantinjected into the laminar flow of the polymer stream traversing throughthe static mixing assemblies 208 is not uniformly mixed into the polymerstream prior to being received by the spinning machine 212.

While, in various embodiments, providing a static mixing assembly 208with fewer individual static mixing elements (i.e., static mixingelements 700 or helical static mixing elements 904) may create a tonalcolor characteristic in the resulting polymer stream, variousembodiments described herein may produce tonal color effects, whileallowing for the same BCF manufacturing system to be utilized to createboth uniformly-colored BCF and BCF having tonal color effects with, invarious embodiments, minimal time and effort in changing the system setup between manufacturing runs of the two products.

Turning to FIG. 13, a static mixing assembly 208 is shown having anumber of individual static mixing elements 700, 904 coupled together tocreate a length of the static mixing assembly 208 through which thepolymer stream flows and mixes. It should be appreciated that forclarity purposes, the static mixing assembly 208 is shown with a reducedquantity of individual static mixing elements 700, 904 shown in FIG. 13.As disclosed herein, the static mixing assembly 208 of variousembodiments may have more than thirty (i.e., thirty six or forty)individual static mixing elements 700, 904.

According to various embodiments, the static mixing assembly 208 has oneor more colorant ports 1302 a-n (collectively referred to as colorantports 1302), and/or liquid injection nozzles, positioned along a lengthof the static mixing assembly 208. The one or more colorant ports 1302may include any type of port suitable for facilitating the injection ofcolorant from one or more colorant container 1304 into the polymerstream within the static mixing assembly 208. According to oneembodiment, the one or more colorant ports 1302 include threads forreceiving the one or more colorant containers 1304 and/or one or moremechanisms coupled to the one or more colorant containers 1304. In otherembodiments, the one or more colorant ports 1302 and the one or morecolorant containers 1304 are coupled together via a quick-disconnectconnection 1306 that allows for easy and rapid connection of the one ormore colorant containers 1304 to/from the colorant ports 1302.

Once a colorant container 1304 is connected to a respective colorantport 1302, colorant may be injected from the container, through the portand into: (1) a location that is adjacent the center of the polymerstream within the static mixing assembly 208; (2) a location proximateto an inside wall of the housing 702 of the static mixing assembly 208;and/or (3) any other suitable location. Injecting the colorant into thecenter of the polymer stream may result in more uniform or predictablemixing, while injecting the colorant into the polymer stream proximateto a wall of the static mixing assembly's housing 702 may yield moredistinct tonal color effects in the resulting colored polymer stream andcorresponding BCF product.

FIG. 13 shows three pairs of colorant ports 1302 a-n positioned in threedifferent locations along the length of the static mixing assembly 208,and four individual colorant ports 1302 c-1302 f It should beappreciated that any number of colorant ports 1302 a-n may be used ateach respective distance along the length of the static mixing assembly208, and that groups of one or more colorant ports 1302 a-n may bepositioned at any respective distance along the length of the staticmixing assembly 208 without departing from the scope of this disclosure.In particular embodiments, one or more colorant ports are positionedbetween each of at least 2, 3, 4, 5, 6, 7, or 8 consecutive respectiveadjacent pairs of mixing elements within the mixing assembly.

For example, while the one or more colorant ports 1302 are shown inpairs at each location, various embodiments may utilize only a singlecolorant port 1302 at each location, or may alternatively utilize morethan two colorant ports 1302 at each location along the length of thestatic mixing assembly 208. According to an alternative embodiment, thepositioning of the one or more colorant ports 1302 around thecircumference of the static mixing assembly 208 may differ. For example,a first colorant port 1302 a may be positioned on a top side (i.e., atthe zero degree location when viewing the circular cross-section) of thestatic mixing assembly 208, while a second colorant port 1302 b that islocated downstream along the length of the static mixing assembly 208may be positioned on the right side (i.e., at the 90 degree locationwhen viewing the circular cross-section) of the static mixing assembly208. The various radial positioning around the circumference of thestatic mixing assembly 208 may yield different tonal color effects inthe colored polymer stream exiting the static mixing assembly 208 if thecolorant is injected within the polymer stream at a location other thancentrally (i.e., proximate to the wall of the housing 702).

The static mixing assembly 208 shown in FIG. 13 has one or more colorantports 1302 a positioned at the upstream end 1308 of the static mixingassembly 208 where the polymer stream enters. As described above,providing colorant at the upstream end 1308 may result in a uniform mixand corresponding uniformly colored polymer stream exiting thedownstream end 1310 of the static mixing assembly 208. However, ifcolorant is added at locations downstream of the upstream end 1308, lessmixing of the colorant with the polymer stream may occur, resulting in atonal color effect. As discussed, colorant added at the one or morecolorant ports 1302 n positioned within 5 to 20 individual static mixingelements from the downstream end 1310 of the static mixing assembly 208,the resulting colored polymer stream is most likely to possess distincttonal color effects that may be formed into a tonal yarn using one ormore spinning machines 212.

According to one embodiment, multiple colorant containers 1304 (e.g.,that are configured to selectively deliver liquid colorant underpressure—e.g., via a suitable pump arrangement, such as any suitablepump arrangement described below) may be utilized simultaneously withmultiple corresponding colorant ports 1302 at different locations alongthe length of the static mixing assembly 208 to create tonal coloreffects with multiple colors. For example, a first one or more colorantcontainers 1304 having a first color may be coupled to the one or morecolorant ports 1302 b, while a second one or more colorant containers1304 having a second color may be coupled to the one or more colorantports 1302 n. The resulting colored polymer stream may contain tonalcolor effects with respect to the first color that are more subtle thanthe tonal color effects associated with the second color that arepresent in the same colored polymer stream since the polymer stream andthe first color mix for a longer period of time than the colored polymerstream (containing a mix with the first color) and the second color.

Alternatively, according to another embodiment, a first one or morecolorant containers 1304 having a first color may be coupled to the oneor more colorant ports 1302 n shown on the top side of the static mixingassembly 208, while a second one or more colorant containers 1304 havinga second color may be coupled to the one or more colorant ports 1302 nshown on the bottom side of the static mixing assembly 208. In thisembodiment, two different colorants are injected into the polymer streamat different radial locations around the circumference of the staticmixing assembly 208. Doing so may allow the polymer stream, the firstcolorant, and the second colorant to mix for a short length prior toexiting the downstream end 1310 of the static mixing assembly 208 with aunique tonal color effect.

FIG. 14 depicts a high level overview of BCF manufacturing process 1400for producing and coloring BCF with a tonal color effect, for example,for use in the production of carpet and other products. The method ofmanufacturing bulked continuous filaments—as indicated in FIG. 14 by1400, may be split in five steps:

-   -   Pass PET (e.g., or other polymer flakes) through an extruder        that melts the flakes and purifies the resulting PET polymer        (step 1402);    -   Optionally split the extruded polymer melt into a plurality of        melt streams (step 1404);    -   Use a static mixing assembly to mix each of the plurality of        melt streams (step 1406);    -   Add colorant to a static mixing assembly at desired locations        along the length of the mixer to partially mix colorant with the        melt streams (step 1408);    -   Feed each of the melt streams with tonal color effect into a        respective spinning machine that turns the polymer into tonal        filament for use in manufacturing carpets or other products        (step 1410);        thereby ending the method manufacturing bulked continuous        filaments—as indicated in FIG. 14 by 1420.

The process 1400 begins as described above with respect to steps 1 and 2of FIG. 1 above. Specifically, at operation 1402, PET or other polymerflakes are passed through an extruder that melts the flakes and purifiesthe resulting PET polymer. At operation 1404, the extruded polymerstream may then be optionally split into a plurality of polymer streams.At operation 1406, one or more static mixing assemblies 208 may be usedto mix each of the polymer streams. Colorant is added at operation 1408to the one or more static mixing assemblies 208 through one or morecolorant ports 1302. The one or more colorant ports 1302 that are usedfor injecting colorant may be selected based on the location of the oneor more colorant ports 1302 along the length of the one or more staticmixing assemblies 208. The locations of the one or more colorant ports1302 determine the amount of mixing of the one or more colorants withthe polymer stream within the static mixing assembly 208 and the desiredtonal color effect of the resulting BCF product. At operation 1410, eachof the polymer streams with the desired tonal color effects are fed intoa respective spinning machine 212 to turn the polymer into a tonalfilament for use in manufacturing carpets or other products, asdescribed in further detail below.

Step 4: Use of a Spinning Machine to Turn the Colored Polymer intoFilament

Referring back to FIG. 2, after the polymer melt and the added coloranthave been sufficiently mixed using the one or more static mixingassemblies 208 (e.g., homogeneously mixed), the resultant colored meltstream may be fed directly into BCF (or “spinning”) machine 212 that isconfigured to turn the molten polymer into bulked continuous filament(See FIG. 2). In particular embodiments, the spinning machine 212extrudes molten polymer through small holes in a spinneret in order toproduce carpet yarn filament from the polymer. In particularembodiments, the molten recycled PET polymer cools after leaving thespinneret. The carpet yarn is then taken up by rollers and ultimatelyturned into filaments that are used to produce carpet. In variousembodiments, the carpet yarn produced by the spinning machine 212 mayhave a tenacity between about 3 gram-force per unit denier (gf/den) andabout 9 gf/den. In particular embodiments, the resulting carpet yarn hasa tenacity of at least about 3 gf/den.

In particular embodiments, the spinning machine 212 used in the processdescribed above is the Sytec One spinning machine manufactured byOerlikon Neumag of Neumuenster, Germany. The Sytec One machine may beespecially adapted for hard-to-run fibers, such as nylon orsolution-dyed fibers, where the filaments are prone to breakage duringprocessing. In various embodiments, the Sytec One machine keeps the runsdownstream of the spinneret as straight as possible, uses only onethreadline, and is designed to be quick to rethread when there arefilament breaks.

Although the example described above describes using the Sytec Onespinning machine to produce carpet yarn filament from the polymer, itshould be understood that any other suitable spinning machine may beused. Such spinning machines may include, for example, any suitableone-threadline or three-threadline spinning machine made by OerlikonNeumag of Neumuenster, Germany or any other company.

In various embodiments, prior to using the spinning machine 212 to spinthe colored melt into filament, the process may utilize one or morecolor sensors 210 to determine a color of the colored melt. In variousembodiments, the one or more color sensors 210 comprises one or morespectrographs configured to separate light shone through the polymermelt into a frequency spectrum to determine the color of the polymermelt. In still other embodiments, the one or more color sensors 210comprises one or more cameras or other suitable imaging devicesconfigured to determine a color of the resultant polymer melt. Inparticular embodiments, in response to determining that the color of thepolymer melt is a color other than a desired color (e.g., the polymermelt is lighter than desired, darker than desired, a color other thanthe desired color, etc.) the system may: (1) discard the portion of thestream with the incorrect color; and/or (2) adjust an amount of colorant204 that is added to the flake and/or the polymer melt upstream in orderto adjust a color of the resultant polymer melt. In particularembodiments, adjusting the amount of colorant 204 is executed in asubstantially automated manner (e.g., automatically) using the one ormore color sensors 210 in a computer-controlled feedback control loop.

Producing a Plurality of Different Colored Fibers Using a Single PrimaryExtruder

In addition to the single colorant added to a single polymer stream froma primary extruder 202 described above with respect to FIG. 2, theprocess described herein may be utilized to produce a plurality ofdifferent colored filament from a single primary extruder. FIG. 11depicts a process for producing a plurality of different coloredfilament from a single primary extruder (e.g., a single MRS extruder)according to a particular embodiment. As may be understood from FIG. 11,the process involves splitting the polymer melt from the primaryextruder 202 into a plurality of individual polymer streams 203 a-d(e.g., four individual polymer streams) using any suitable technique. Inother embodiments, the process may include splitting the polymer meltfrom the primary extruder 202 into any suitable number of individualpolymer streams (e.g., two individual polymer streams, three individualpolymer streams, four individual polymer streams, five individualpolymer streams, six individual polymer streams, seven individualpolymer streams, eight individual polymer streams, etc.)

As shown in this Figure, a colorant (e.g., Colorant A-D 204 a-d whereinColorant A is indicated as 204 a, Colorant B is indicated as 204 b,Colorant C is indicated as 204 c and Colorant D is indicated as 204 d)is added to each individual polymer stream, for example, using arespective extruder 206 a-d as described above. For example, Colorant C204 is added to individual polymer stream 203 c using extruder 206 c.

Once the respective Colorant A-D 204 a-d has been added to therespective individual polymer stream 203 a-d, each individual polymerstream 203 a-d with added Colorant A-D 204 a-d is substantiallyuniformly mixed using respective one or more static mixing assemblies208 a-d. For example, once Colorant D 204 d has been added to individualpolymer stream 203 d, the resultant colorant/polymer mixture passesthrough the one or more static mixing assemblies 208 d to mix theColorant D 204 d and individual polymer stream 203 d (e.g., tosubstantial homogeneity). Following mixture by the one or more staticmixing assemblies 208 a-d, the resultant respective colored melt streamsare spun into filament using respective spinning machines 212 a-d.

In various embodiments, it may be important to monitor the output of theextruder to determine a throughput of each individual polymer stream 203a-d. In such embodiments, monitoring throughput may ensure that eachindividual polymer stream 203 a-d has the proper color letdown ratio inorder to add a proper amount of Colorant A-D 204 a-d to achieve adesired color of bulked continuous filament.

As may be understood from FIG. 11, splitting extruded polymer from aprimary extruder 202 into a plurality of polymer streams 203 a-d priorto the addition of colorant may enable the production of a plurality ofcolored filament using a single primary extruder 202. Furthermore, byusing a plurality of different colorants and extruders downstream of theprimary extruder 202, the process may facilitate a reduction in wastewhen changing a colorant used. For example, when using a single extruderin which color is added upstream of the extruder, there is wasteassociated with changing over a color package in that the extruder mustrun sufficiently long between changes to ensure that all of the previouscolor has cleared the extruder (e.g., such that none of the previouscolor will remain and mix with the new color). In some embodiments, thewasted filament as a result of a switch in color may include up toseveral thousand pounds of filament (e.g., up to 4000 pounds). Using asmaller secondary extruder 206 a-d to introduce colorant to the variousindividual polymer streams 203 a-d downstream from the primary extruder202 may reduce (e.g., substantially reduce) the amount of wasteassociated with a changeover of colorant (e.g., to below about 100pounds per changeover).

Alternative Embodiments

Various embodiments of a process for producing various colored bulkedcontinuous filament may include features that vary from or are inaddition to those described above. Exemplary alternative embodiments aredescribed below.

Addition of Liquid Colorant to Melt Stream Using Pump

FIG. 12 depicts an alternative process flow for that, in many respectsis similar to the process flow shown in FIG. 11. In the embodiment shownin FIG. 12, however, liquid colorant 214 a-d is added to the individualpolymer streams 203 a-d using a pump 214 a-d rather than an extruder. Invarious embodiments, using a liquid colorant may have the benefit ofadditional cost saving due to not having to use any additional secondaryextruders (e.g., which may have a greater initial cost outlay than apump, greater running costs than a pump, etc.). In particularembodiments in which a pump 214 a-d is used to inject the liquidcolorant 214 a-d into the individual polymer streams 203 a-d, theprocess may further include exchanging a hose used to connect the pump214 a-d to the individual polymer streams 203 a-d when exchanging aparticular liquid colorant (e.g., liquid colorant 204 a) for a differentliquid colorant (e.g., a liquid colorant of a different color). Byexchanging the hose when exchanging colorants, waste may further bereduced in that the replacement hose is pre-purged of any residualcolorant of the previous color.

CONCLUSION

Many modifications and other embodiments of the invention will come tomind to one skilled in the art to which this invention pertains havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. Also, while various embodiments are discussedabove in regard to producing carpet filament from PET, similartechniques may be used to produce carpet filament from other polymers.Similarly, while various embodiments are discussed above in regard toproducing carpet filament from PET, similar techniques may be used toproduce other products from PET or other polymers.

In addition, it should be understood that various embodiments may omitany of the steps described above or add additional steps. Furthermore,any numerical ranges described herein are intended to capture everyinteger and fractional value within the described range (e.g., everyrational number value within the described range). For example, itshould be understood that a range describing a letdown ratio of betweenabout two percent and about eight percent is intended to capture anddisclose every rational number value percentage between two percent andeight percent (e.g., 2%, 3%, 4%, 5%, 6%, 7%, 8%, 2.1%, 2.01%, 2.001% . .. 7.999% and so on). Additionally, terms such as ‘about’,‘substantially’, etc., when used to modify structural descriptions ornumerical values are intended to capture the stated shape, value, etc.as well as account for slight variations as a result of, for example,manufacturing tolerances. For example, the term ‘substantiallyrectangular’ is intended to describe shapes that are both exactlyrectangular (e.g., have four sides that meet at ninety degree angles) aswell as shapes that are not quite exactly rectangular (e.g., shapeshaving four sides that meet at an angle in an acceptable tolerance ofninety degrees, such as 90°+/−4°)

In light of the above, it is to be understood that the invention is notto be limited to the specific embodiments disclosed and thatmodifications and other embodiments are intended to be included withinthe scope of the appended claims. Although specific terms are employedherein, they are used in a generic and descriptive sense only and notfor the purposes of limitation.

We claim:
 1. A method of manufacturing a bulked continuous carpetfilament from polyethylene terephthalate (PET) having a tonal color, themethod comprising: providing an extruder; using the extruder to at leastpartially melt the PET into a polymer melt and at least partially purifythe polymer melt to create a polymer stream; providing a static mixingassembly comprising one or more individual static mixing elements thatare aligned to form a central passageway for the polymer stream to passthrough such that the polymer stream enters an upstream end of thestatic mixing assembly and exits a downstream end of the static mixingassembly, and is mixed by the one or more individual static mixingelements between the upstream end and the downstream end of the staticmixing assembly; providing a plurality of colorant ports positionedalong a length of the static mixing assembly from the upstream end tothe downstream end such that each of the plurality of colorant ports isconfigured to provide colorant to the polymer stream at a differentlocation along the length of the static mixing assembly; using thestatic mixing assembly to mix the polymer stream with the colorantprovided at a colorant port from a position of the colorant port to thedownstream end of the static mixing assembly; and after using the staticmixing assembly to mix the polymer stream with the colorant, forming thepolymer stream into bulked continuous carpet filament having a tonalcolor effect.
 2. The method of claim 1, the method further comprising:injecting the colorant into a colorant port proximate to the downstreamend of the static mixing assembly; and receiving the polymer stream at aspinning machine from the downstream end of the static mixing assemblyhaving a tonal color effect resulting from non-uniform mixing of thecolorant with the polymer stream within the static mixing assembly. 3.The method of claim 2, wherein the colorant port is positioned to injectcolorant into the static mixing assembly two to four static mixingelements from the downstream end of the static mixing assembly.
 4. Themethod of claim 3, wherein the colorant port comprises a first colorantport, and wherein the tonal color effect of the polymer stream receivedat the spinning machine resulting from the colorant injected into thefirst colorant port comprises a first tonal color effect, the methodfurther comprising: stopping the injection of the colorant into thefirst colorant port; and injecting the colorant into a second colorantport at a location along the length of the static mixing assemblyupstream of the first colorant port to create a polymer stream having asecond tonal color effect that is less pronounced than the first tonalcolor effect due to an increased mixing length from the second colorantport to the downstream end of the static mixing assembly as compared toa mixing length from the first colorant port to the downstream end ofthe static mixing assembly.
 5. The method of claim 3, wherein thecolorant port comprises a first colorant port, the method furthercomprising: stopping the injection of the colorant into the firstcolorant port; and injecting the colorant into a second colorant port ata location along the length of the static mixing assembly proximate tothe upstream end of the static mixing assembly to substantiallythoroughly mix the polymer stream with the colorant to change the tonalcolor effect of the polymer stream to a polymer stream having asubstantially uniform color.
 6. The method of claim 1, the methodfurther comprising: providing a plurality of colorant containers coupledto the plurality of colorant ports; and injecting a plurality ofcolorant into the polymer stream at the plurality of locations along thelength of the static mixing assembly.
 7. The method of claim 6, whereinthe plurality of colorant ports each comprise quick disconnect couplingmechanisms configured to allow for the installation and de-installationof a colorant container while the polymer stream traverses through thestatic mixing assembly.
 8. The method of claim 1, the method furthercomprising: splitting the polymer stream into a plurality of individualpolymer streams downstream from the extruder; wherein the static mixingassembly comprises a static mixing assembly for each of the plurality ofindividual polymer streams such that each of the plurality of individualpolymer streams forms into bulked continuous carpet filament having atonal color effect.
 9. The method of claim 1, wherein the extruder is amulti-screw extruder.
 10. The method of claim 1, wherein the staticmixing assembly comprises a substantially cylindrical housingencompassing the one or more individual static mixing elements.
 11. Themethod of claim 1, wherein the one or more individual static mixingelements comprise at least thirty individual static mixing elements. 12.The method of claim 11, wherein the one or more individual static mixingelements comprise thirty six to forty individual static mixing elements.13. The method of claim 1, wherein the one or more individual staticmixing elements comprise at least five individual static mixing elementsarranged consecutively in series, and wherein the plurality of colorantports comprises at least one colorant port corresponding to each of theat least five individual static mixing elements.
 14. The method of claim1, wherein the one or more individual static mixing elements comprise atleast ten individual static mixing elements, and wherein the pluralityof colorant ports comprises at least one colorant port corresponding toeach of the at least ten individual static mixing elements.
 15. Themethod of claim 1, wherein the one or more individual static mixingelements comprises at least two individual static mixing elementsarranged in series, wherein each of the at least two individual mixingelements comprises a housing; and one or more mixing bars or one or morehelical mixing elements.
 16. A system for manufacturing a bulkedcontinuous carpet filament from polyethylene terephthalate (PET) havinga tonal color, comprising: an extruder configured to at least partiallymelt the PET into a polymer melt and at least partially purify thepolymer melt to create a polymer stream; a static mixing assemblypositioned downstream of the extruder and fluidly coupled to theextruder to receive the polymer stream and to create a colored polymerstream, each of the static mixing assembly comprising: a housing, one ormore individual static mixing elements disposed within the housing suchthat the polymer stream enters an upstream end of the static mixingassembly and exits a downstream end of the static mixing assembly, and aplurality of colorant ports along a length of the static mixing assemblyfrom the upstream end to the downstream end such that each of theplurality of colorant ports is configured to provide colorant to thepolymer stream at a different location along the length of the staticmixing assembly; and one or more spinning machines positioned downstreamof the static mixing assembly and fluidly coupled to the static mixingassembly to receive the colored polymer stream, the one or more spinningmachines configured to form the colored polymer stream into bulkedcontinuous carpet filament having a tonal color effect.
 17. The systemof claim 16, wherein the plurality of colorant ports comprises: a firstcolorant port positioned proximate to the upstream end of the staticmixing assembly such that colorant injected through the first colorantport is uniformly mixed over the length of the static mixing assembly tocreate a uniformly colored characteristic of the colored polymer stream;and a second colorant port positioned downstream of the first colorantport such that colorant injected through the second colorant port mixeswith the polymer stream for a distance shorter than the length of thestatic mixing assembly to create a tonal effect characteristic of thecolored polymer stream.
 18. The system of claim 16, further comprisingone or more colorant containers coupled to the one or more colorantports.
 19. The system of claim 18, wherein the one or more colorantcontainers are coupled to the one or more colorant ports via quickdisconnect coupling mechanisms configured to allow for the installationand de-installation of a colorant container while the polymer streamtraverses through the static mixing assembly.
 20. The system of claim16, wherein the static mixing assembly comprises a plurality of staticmixing assemblies, each static mixing assembly receiving an individualpolymer stream of a plurality of individual polymer streams split fromthe polymer stream downstream of the extruder.
 21. The system of claim16, wherein one or more colorant ports are positioned to inject colorantinto the static mixing assembly two to four static mixing elements fromthe downstream end of the static mixing assembly.
 22. The system ofclaim 16, wherein one or more colorant ports are positioned to injectcolorant into the static mixing assembly at different positions around acircumference of the static mixing assembly.